In an image compression method, such as Moving Picture Experts Group (MPEG)-1, MPEG-2, MPEG-4, or H.264/MPEG-4 Advanced Video Coding (AVC), a picture is divided into macroblocks in order to encode an image. Each of the macroblocks is encoded in all encoding modes that can be used in inter prediction or intra prediction, and then is encoded in an encoding mode that is selected according to a bit rate used to encode the macroblock and a distortion degree between a decoded macroblock and the original macroblock.
As hardware for reproducing and storing high resolution or high quality video content is being developed and supplied, there is an increasing need for a video codec capable of effectively encoding or decoding the high resolution or high quality video content. In a conventional video codec, a video is encoded in units of macroblocks each having a predetermined size.